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Insect Order Trichoptera (Caddisflies)

Pictures Below
Some say caddisflies are even more important than mayflies, and they are probably right. The angling world has taken a while to come to terms with this blasphemy. Caddis imitations are close to receiving their fare share of time on the end of the tippet, but too many anglers still assume all caddisflies are pretty much the same.

Caddis species actually provide as much incentive to learn their specifics as the mayflies do. There is just as much variety in their emergence and egg-laying behaviors, and as many patterns and techniques are needed to match them. Anglers are hampered only by the relative lack of information about caddisfly behavior and identification.

Hatching Behavior


In many species, the pupae become very active just before emergence and drift along the bottom of the river, sometimes for hours. The "deep sparkle pupa" patterns introduced by Gary LaFontaine in Caddisflies are the most popular of many imitations inspired by this behavior. It is a deep nymph fisherman's dream. Sometimes they drift similarly just below the surface for a long time before trying to break through.

Pupae of different species use three different methods to emerge:

  • Most species rise to the surface and struggle through. They usually take flight quickly once they're out of the water, but slow species first struggle and drift long distances half-submerged as they wriggle free from their pupal shucks (
    Here's an underwater view of the pupal shucks of several already-emerged Brachycentrus numerosus caddisflies.
    Here's an underwater view of the pupal shucks of several already-emerged Brachycentrus numerosus caddisflies.
    Shuck: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult.
    )
    .

  • The pupae of some species crawl out of the water on rocks, sticks, and such, so that the adults emerge high and dry.

  • Some pupae rise to the surface and swim quickly across it to shore where they crawl out to emerge.


Most caddis pupae are good swimmers, and they use their legs as paddles rather than wiggling their bodies to move.

After emerging, caddisfly adults live for a long time compared to mayflies, in part because they are able to drink to avoid dehydration (mayfly adults cannot eat or drink). This flight period (Flight period: The span of time that the adults of an adult aquatic insect species are active and flying around, in between emergence and death. It may refer to the average adult lifespan of the individuals of that species, or to the total length of time for which at least some of them are active.) lasts anywhere from a few days to a few months, depending on the species, so mating adults may be seen on or over the water long after emergence is complete.

Egg-Laying Behavior


Many caddisfly females dive underwater to lay their eggs on the stream bottom. Some crawl down objects to do this but most swim right down through the water column. The latter are responsible for my fastest trout fishing action ever -- days when trout raced each other to attack my flies the moment they hit the water, cast after cast.

Others lay their eggs on the surface in various ways. They may fly low over the water, periodically dipping their abdomens to lay eggs. Others land on the surface repeatedly, fussing and fluttering in enticing commotion. Less active species may fall spent (Spent: The wing position of many aquatic insects when they fall on the water after mating. The wings of both sides lay flat on the water. The word may be used to describe insects with their wings in that position, as well as the position itself.) to the surface with all four wings spread out. Others ride the water serenely while laying their eggs, and they are the easiest to match with the dead-drift (Dead-drift: The manner in which a fly drifts on the water when not moving by itself or by the influence of a line. Trout often prefer dead-drifting prey and imitating the dead-drift in tricky currents is a major challenge of fly fishing.) techniques of mayfly fishermen.

Some egg-laying methods keep the adult females safe from trout altogether. They may drop their eggs into the water from overhanging plants, or lay their eggs on the vegetation itself. That way the eggs don't enter the river until the next rain--an excellent drought survival strategy.

Larva & Pupa Biology


Most caddisfly larvae live in cases they build out of sand, rock, twigs, leaf pieces, and any other kind of underwater debris. Some even generate their own cases out of silk. There is tremendous variation in case style and also in the way the larvae manage their cases: whether they replace it as they grow or renovate their old one, and whether they carry it around or fix it to an object. Trout love to eat these larvae, case and all.

Other common caddis larvae build nets instead of cases. These are not residences but hunting traps, like tiny spider webs, designed to capture plankton and smaller aquatic insects the larvae eat. One larva may build more than one net and roam freely around the rocks and logs tending to each and ingesting the catch. The net-spinning families, in order of abundance, are Hydropsychidae, Philopotamidae, and Arctopsychidae.

One large and primitive family of caddisflies, Rhyacophilidae, needs neither cases nor nets. Most of its species are predators who stalk through rocky riffles killing other insect larvae and nymphs.

All of these types are especially prone to behavioral drift (Behavioral drift: The nymphs and larvae of many aquatic insects sometimes release their grip on the bottom and drift downstream for a while with synchronized timing. This phenomenon increases their vulnerability to trout just like emergence, but it is invisible to the angler above the surface. In many species it occurs daily, most often just after dusk or just before dawn.), making them an important food source year-round for the trout in most rivers.

When caddis larvae are full-grown, they seek hiding places to pupate, either in their cases or in special cocoons. They are considered to be pupae throughout the radical reformation from grub-like larva into intricate winged adult. Some of the larva's body mass is consumed as energy for the development of the pupa, so the pupae and adults both have bodies one to three hook sizes smaller than their mature larvae. When pupation is complete, the insect which begins the emergence sequence is called a pharate adult (Pharate adult: Caddisflies are considered to be pupae during their transformation from larva into adult. This transformation is complete before they're ready to emerge. The emerging insect we imitate with the "pupa" patterns we tie is technically called a pharate adult. It is a fully-formed adult caddisfly with one extra layer of exoskeleton surrounding it and restricting its wings.). It is no longer technically a pupa in the language of entomologists, but because anglers universally recognize the term "pupa" I use that convenional misnomer throughout this site.

Sometimes individuals within the same fall-emerging species mature at different rates. In some species, mature larvae compensate for this by entering an inactive phase called diapause (Diapause: A state of complete dormancy deeper even than hibernation. While in diapause, an organism does not move around, eat, or even grow. Some caddisfly larvae enter diapause for a few weeks to several months. Some species of microscopic zooplankton can enter diapause for several hundred years.) prior to pupation. Cool fall weather triggers the end of this phase for every individual within a few short weeks, synchronizing emergences that would otherwise be spread over several months. This boosts the quality of autumn caddisfly hatches like the giant western genus Dicosmoecus.

Trichoptera Fly Fishing Tips


The presence of caddisfly adults in the air does not mean that the angler should immediately switch to an imitation. As Swisher and Richards put it in Selective Trout:

They are often seen over the water when they are doing nothing more than flying around.

More often it's the caddisflies you don't see that are important, the females diving underwater to lay their eggs or the pupae drifting below the surface preparing to emerge.

Pictures of 95 Caddisfly Specimens:

Specimen Page:1234...11
Neophylax (Autumn Mottled Sedges) Caddisfly AdultNeophylax (Autumn Mottled Sedges) Caddisfly Adult View 20 PicturesThis large caddisfly looks really neat close-up.
Collected September 19, 2006 from Mystery Creek #43 in New York
Added to Troutnut.com by Troutnut on October 4, 2006
Brachycentrus appalachia (Apple Caddis) Caddisfly AdultBrachycentrus appalachia (Apple Caddis) Caddisfly Adult View 13 PicturesI captured this specimen in the same color as this photograph, during its egg-laying flight. The emergers are much lighter.
Collected May 13, 2007 from the West Branch of the Delaware River in New York
Added to Troutnut.com by Troutnut on May 18, 2007
Specimen Page:1234...11

9 Streamside Pictures of Caddisflies:

Streamside Photo Page:12
Caddis on Catskill cobble.  In this picture: Insect Order Trichoptera (Caddisflies). From the Beaverkill River in New York.
Caddis on Catskill cobble.

In this picture: Insect Order Trichoptera (Caddisflies).
Date TakenApr 16, 2005
Date AddedFeb 2, 2006
AuthorTroutnut
These caddisflies were thick over the water in the evening on a cold, clear northwoods lake.  They were in many places on the lake, all closer to the shady shore, which also was the shore most sheltered from the wind.  I'm not sure which of those features attracted them.  In this picture: Caddisfly Genus Nectopsyche (White Millers). From Lake Owen in Wisconsin.
These caddisflies were thick over the water in the evening on a cold, clear northwoods lake. They were in many places on the lake, all closer to the shady shore, which also was the shore most sheltered from the wind. I'm not sure which of those features attracted them.

In this picture: Caddisfly Genus Nectopsyche (White Millers).
LocationLake Owen
Date TakenJun 10, 2006
Date AddedJun 30, 2006
AuthorTroutnut
I saw something strange flying around near the streambank, fluttering on and off the water's surface, so I went to check it out.  I didn't recognize the wing profile in flight, and it's no surprise!  These two caddisflies were joined mating, and they were very reluctant to let go.  In this picture: Caddisfly Family Hydropsychidae. From the Neversink River in New York.
I saw something strange flying around near the streambank, fluttering on and off the water's surface, so I went to check it out. I didn't recognize the wing profile in flight, and it's no surprise! These two caddisflies were joined mating, and they were very reluctant to let go.

In this picture: Caddisfly Family Hydropsychidae.
Date TakenMay 20, 2007
Date AddedJun 5, 2007
AuthorTroutnut
CameraPENTAX Optio WPi
Streamside Photo Page:12

55 Underwater Pictures of Caddisflies:

Underwater Photo Page:1234...7
Hundreds of cased caddisfly larvae live on this log in a small brook trout stream.  In this picture: Insect Order Trichoptera (Caddisflies). From Eighteenmile Creek in Wisconsin.
Hundreds of cased caddisfly larvae live on this log in a small brook trout stream.

In this picture: Insect Order Trichoptera (Caddisflies).
Date TakenApr 14, 2004
Date AddedJan 25, 2006
AuthorTroutnut
Shown Full Size
AddEmail
A Brachycentrus "Apple Caddis" pupa scoots around in the surface film.  Apparently it had some difficulty emerging, so I was able to slip my camera underneath it and take a picture from below.  In this picture: Caddisfly Species Brachycentrus appalachia (Apple Caddis). From the East Branch of the Delaware River in New York.
A Brachycentrus "Apple Caddis" pupa scoots around in the surface film. Apparently it had some difficulty emerging, so I was able to slip my camera underneath it and take a picture from below.

In this picture: Caddisfly Species Brachycentrus appalachia (Apple Caddis).
Date TakenApr 19, 2006
Date AddedApr 22, 2006
AuthorTroutnut
CameraPENTAX Optio WPi
This picture from below shows a stillborn Ephemerella subvaria (Hendrickson) dun drifting on the surface amidst a number of shed pupal skins from Brachycentrus caddisflies which were heavily hatching that day.  In this picture: Mayfly Species Ephemerella subvaria (Hendrickson) and Caddisfly Species Brachycentrus appalachia (Apple Caddis). From the East Branch of the Delaware River in New York.
This picture from below shows a stillborn (
This stillborn Ephemerella subvaria dun is trapped in its shuck.
This stillborn Ephemerella subvaria dun is trapped in its shuck.
Stillborn: In fly fishing, a stillborn insect is one which got stuck in its nymphal or pupal shuck during emergence and floats helplessly on the surface instead of flying away. It is a specific class of cripple, although it is sometimes used interchangeably with that term.
)
Ephemerella subvaria (Hendrickson) dun drifting on the surface amidst a number of shed pupal skins from Brachycentrus caddisflies which were heavily hatching that day.

In this picture: Mayfly Species Ephemerella subvaria (Hendrickson) and Caddisfly Species Brachycentrus appalachia (Apple Caddis).
Date TakenApr 19, 2006
Date AddedApr 22, 2006
AuthorTroutnut
CameraPENTAX Optio WPi
Underwater Photo Page:1234...7

Recent Discussions of Trichoptera

Polycentropodidae or? 14 Replies »
Posted by LowBudget on Oct 1, 2013 in the family Polycentropodidae
Last reply on Jul 24, 2014 by Crepuscular
The first image is of a live caddis. It was collected from Trout Creek which is in the Delaware River watershed in upstate NY. The background is 1/4 inch ruled graph paper which is under the Petrie dish holding the caddis with water.

(User-posted images are only viewable in the forum section.)


The second shows small silk nets found on rocks in the same stream during the same sampling.


(User-posted images are only viewable in the forum section.)



I've been working all of my ID books including "Freshwater Macroinvertebrates of Northeastern North America" by Peckarsky.

The upper lip does not seem to have the T shape of a Fingernet caddis. It does have the heavy mandible with a brush of Polycentropodidae.

But, I'm not completely satisfied.

Anyone have thoughts on this?

Ed
ReplyArctopsyche Grandis 6 Replies »
Posted by Epeorus on Jul 2, 2014 in the genus Arctopsyche
Last reply on Jul 6, 2014 by Entoman
A while ago there was some discussion of this bug in Colorado. I first came across this beast in early July 2011 on the Eagle River, just downstream of Edwards, Co. Met him again this week on the Eagle. It's quite the blast - big bugs and big trout. Especially the ones rising with abandon in the fast water in the middle of the day.

Funny thing is we don't seem to see these guys most years. The commonality between 2011 and this year is an extended runoff leading to cold and high - though clear water in early July. I wonder if they normally hatch during the peak of the runoff when no one is on the water.

I remember people commenting about these caddis allegedly being in parts of Colorado. The hatches the last two days on the Eagle and what I saw in 2011 would add some level of credence to that belief.

A size 10 (on a Partridge L3A) sponge body caddis with a dark gray body, and a size 10 Lafontaine sparkle emerger with a gray body and a clear shroud were the ticket.
ReplyMoved from genus level to N. albida
Posted by Entoman on Jun 15, 2014 in the species Nectopsyche albida
It is my understanding that wing maculation is quite distinctive and consistent in this genus thus allowing species identification using this character. This specimen has been at the genus level for many years and somehow slipped through the cracks.;)
ReplyTiny Black Caddis hatch, late fall - Nov 26 to be exact_ Spring Creek Southern MO 20 Replies »
Posted by Dai_sca on Dec 29, 2010 in the family Hydroptilidae
Last reply on Jun 11, 2014 by Motrout
I had not fished Bennett Spring for many years and ended up there on Nov 26. I was not very prepared for the stream's entemology, spoke to someone at the flyshop and went with fishing a midge or two and this was very successful. But it was quite obvious that the trout were feeding on the surface or just under and it wasn't a midge. As the day progressed and late afternoon brought sunshine, a hatch of Tiny Caddis(Black) appeared. I had a size 18 but it wasn't dark enough or small enough. A gent who fished the stream regularly gave me a #24 black Elk Hair(or other hair) caddis. The fish took this fly as a dry off the surface. I am hard pressed to ID this fly aside from Protoptila. This, however, is not a marginally temp spring, the water is consistent flow a cold. The description of the Protoptila indicates that this insect is more a warm water insect. The hatch was occurring right at the spring itself. Any ideas?

Again, this was a size 24 fly, and maybe,just maybe, a 26 or 28 might have been the appropriate size for the insect as there were obvious refusals at the surface.

David (dai_sca@yahoo.com
ReplyArctopsyche grandis 6 Replies »
Posted by Flymonster on Sep 8, 2011 in the species Arctopsyche grandis
Last reply on May 20, 2013 by Flymonster
Here in the Willamette Valley the McKenzie Caddis (as Arctopsyche grandis is known locally) usually begins its emergence sometime around mid-May and can continue into mid-June. The most emergence activity will be noted on warm days once the water temperature reaches @ 52f. Most hatches occur on warm sunny days from 4pm-7pm. Arlen Thomason goes into great detail about the life-cycle and behaviors of a. grandis in his book "Bug Water".

At least for me, the McKenzie Caddis, marks the beginning of summer and excellent fly fishing for trout on the McKenzie, Middle Fork Willamette, North Fork of the Middle Fork Willamette, and our other local rivers and streams.
Reply
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